From D&D Wiki
|Range:||Medium (100ft. + 10ft./level)|
|Target, Effect, or Area:||Creature Casting Spell|
Not so much as a counter to a spell, rather then a means to rewind the caster and prevent it from being casted while the caster still losses a slot for the spell. This spell cannot be used on physical attacks.
Counter Spell is able to prevent any spell 1 level lower then your current casting level and only spells that are currently being casted. A save vs. Will and the target must make a concentration check or the spell still fizzles. For example: Tristan is locked into battle with another magic user who just casted a level 3 spell. Tristan being that he is a level 8 and is able to cats 4th level magic is able to counter the spell and does so, but the magic user saved vs. will only to fail the concentration check and the spell still fizzles.
The casting time of this spell is instantaneous so as long as the caster is holding the material component in their hand while the spell was casted by the opponent.
Material Component: Sand from an hourglass to be thrown in the general direction of the target caster.